The world is full of sealing members for use in applications wherein the sealing member functions to seal a bearing from the influx of dirt and grime to retain lubrications such as found in U.S. Pat. No. 3,203,740. Another sealing member typically used in an "o" ring seal which is used to maintain the pressure and fluid on one side of the seal from "leaking" to the other side of seal such as is found in the assembly of fuel injectors to internal combustion engines.
Seals are used to rotate around a housing member such as found in U.S. Pat. No. 4,099,731 wherein the seal rotates with a roll as in a rolling mill. Seals are used as packing materials in applications where in the water or fluid under pressure is to remain on the one side of the seal and not "leak" through to the other side. Seals are used to occupy the space between mating parts to accept normal manufacturing tolerances on such mating parts; an example of such a seal is U.S. Pat. No. 4,383,694.
Seals are made from polytetrafluoroethylene (PTFE) material to function as gaskets. An example of such a PTFE seal is found in EP A2 0 352 608. In each of these types of seals, the pressure differential across the seal is typically high and as such the devices have hard external surfaces and are slightly deformable in order to mate in tight places.